Hydraulic control system and front-mounted rear-drive hydraulic automatic gearbox comprising same
Technical Field
The invention relates to an automobile gearbox, in particular to a novel hydraulic control system and a front-mounted rear-drive 6-speed hydraulic automatic gearbox comprising the hydraulic control system.
Background
The gearbox is used as an important part for shifting gears when a vehicle runs, and a hydraulic control system on the gearbox is generally used for shifting high and low gears. Shift comfort is an important indicator of a transmission. In the conventional hydraulic control system of the automatic transmission, in order to reduce the impact of gear shifting and improve the comfort of gear shifting when a gearbox is downshifted (particularly when the gear 2 is downshifted by 1), a structure of a one-way clutch is mostly adopted as shown in figure 4 (in the figure, 4-1 is a roller, 4-2 is a spring and 4-3 is an inner ring). After the power transmission is interrupted, the engine load is decreased and the engine speed is increased, and when the engine speed is increased to the engine speed required by the vehicle speed under the gear ratio condition after the downshift, the one-way clutch is engaged to resume the power transmission. In the downshift process, if the vehicle speed and the engine rotating speed are not matched on the basis of the transmission ratio after the downshift, the one-way clutch is not combined, and the power transmission is interrupted; if the two-way clutch is matched, the one-way clutch is combined, power transmission is recovered, and therefore the impact phenomenon cannot occur, and the downshift impact is eliminated. Considering that the gearbox is in a forward function state, the one-way clutch must be considered to be not used when the hydraulic control system is designed for realizing an engine braking function, so that the one-way clutch is mostly arranged in series with a brake or a clutch, and the arrangement of the one-way clutch in the gearbox is concretely shown in FIG. 5 (wherein F0/F1/F2 are all the one-way clutches, B0/B1/B2/B3 are braking clutches, and C0/C1/C2 are transmission clutches), so that the logic of the hydraulic control system of the gearbox is complicated, the overall structural size of the gearbox is increased, and the manufacturing cost is increased.
Disclosure of Invention
In order to make up for the defects in the prior art, the invention aims to provide a hydraulic control system which is applicable to a large-torque commercial vehicle without adopting a one-way clutch, can effectively improve the gear shifting quality and reduce the gear shifting impact, and a front-mounted rear-drive 6-speed hydraulic automatic gearbox applying the hydraulic control system.
In order to achieve the purpose, the invention adopts the technical scheme that:
a hydraulic control system including a torque converter, characterized in that: the hydraulic transmission consists of a high-pressure oil path, a gear switching oil path, a locking separation oil path and a lubricating oil path, and switching of P/R/N/D gears is realized by controlling the switching states of 5 hydraulic actuating mechanisms (a first clutch, a second clutch, a third brake, a fourth brake and a fifth clutch), wherein the D gear is divided into six gears D1/D2/D3/D4/D5/D6; the hydraulic torque converter is controlled to be switched between a locking state and an unlocking state according to different working conditions, the working conditions needing torque increase, such as starting/climbing, are in the unlocking state, and the working conditions are in the locking state after a certain vehicle speed is reached, so that high transmission efficiency is guaranteed.
The gear switching oil path comprises an A valve 1, a one-way throttle valve 2, the fourth brake 3, a B valve 4, an electromagnetic valve 5, a C valve 6, a pressure release valve 7, a D valve 8 and a fourth brake reaction cavity 9; the valve A1 is independently installed in a valve core hole, a spring is installed on the outer side of the valve core hole, the outermost side of the valve core hole is sealed by a plug, the one-way throttle valve 2 is communicated with an oil inlet of the valve A1 on a valve plate, the valve B4, the valve C6 and the valve D8 are independently installed in the valve core hole, and the outer side of the hole is sealed by the plug; the relief valve 7 is communicated with a left hole of a valve core hole where the valve B4 is located, and an oil supply path of the electromagnetic valve 5 is respectively communicated with the rightmost sides of the valve core holes where the valve A1, the valve C6 and the valve D8 are located and is also communicated with a valve core where the valve B4 is located.
When the gear is in a second gear, the electromagnetic valve 5 does not work, the output pressure is 0, the control oil pressure of the leftmost side of the valve A1, the leftmost side of the valve C6 and the leftmost side of the valve D8 is 0, the valve A1, the valve C6 and the valve D8 are all positioned at the rightmost side of the empty valve core under the action of the spring, and in the state, the main oil pressure enters the fourth brake reaction cavity 9 from the core hole of the valve D8; the feedback oil pressure of the brake enters the right end of the B valve 4 through the hole of the C valve 6, so that the B valve 4 moves leftwards, and the oil in the oil chamber of the fourth brake is discharged through the pressure release valve.
A closed independent brake oil cavity is formed in the fourth brake 3, a fourth brake reaction cavity 9 is also formed in the fourth brake 3, and when pressure oil enters the fourth brake oil cavity from an inlet of the brake oil cavity, the fourth brake oil cavity is expanded, and the volume of the fourth brake reaction cavity 9 is compressed, so that the oil in the fourth brake reaction cavity 9 is removed; when pressure oil enters from the inlet of the fourth brake reaction chamber 9, the fourth brake reaction chamber 9 can be enlarged, and the volume of the fourth brake oil chamber can be correspondingly compressed, so that the oil in the fourth brake oil chamber is discharged.
And in the second gear, the first clutch and the third brake work, the working state of the first clutch provides a high-pressure oil supply way for the gear shifting valve, the electromagnetic valve and the slide valve keep the first clutch in a combined state, the system oil way of the third brake supplies high-pressure oil, the electromagnetic valve and the slide valve keep the third brake in a combined state, the reaction cavity of the fourth brake is filled with oil, and the fourth brake is disconnected.
In the first gear, the first clutch and the fourth brake work. The working state of the first clutch provides a high-pressure oil supply path for the gear shifting valve, and the electromagnetic valve and the slide valve keep the first clutch in a combined state. The fourth brake is filled with oil, and the reaction chamber of the fourth brake is disconnected. The solenoid valve + spool valve maintains the third brake in a pre-charge state.
When the gearbox executes gear shifting from a second gear to a first gear, the hydraulic control system firstly finishes a pre-oil filling process for a fourth brake 3, an oil circuit of the fourth brake 3 finishes basic oil pressure (pre-oil filling), the current of an electromagnetic valve 5 is controlled to enable the electromagnetic valve 5 to output proper pressure oil, the pressure oil enables a valve B4 to move rightwards, and main oil pressure enters an oil cavity of the brake to finish pre-oil filling; because the fourth brake reaction cavity 9 is also filled with certain pressure oil in the relation of controlling oil pressure, the electromagnetic valve 5 finishes the quick oil filling time of the brake at the moment of switching the first gear.
Has the advantages that: through the interrelation of 4 valves of A B C D valve, the problem of 2-gear-down 1-gear shift impact is effectively solved, one electromagnetic valve controls two oil cavities simultaneously, the cost is effectively saved, the actions of a brake and a reaction cavity have linkage property, different working conditions can be better adapted, and the shift quality can be effectively improved.
Drawings
FIG. 1 is a schematic diagram of the operating states of a second gear A-D spool valve according to an embodiment of the present invention.
Fig. 2 is a schematic view of a brake actuator according to an embodiment of the present invention.
FIG. 3 is a schematic view of the operating states of the first gear A-D spool valve of the embodiment of the present invention.
Fig. 4 is a schematic diagram of the operation of a prior art one-way clutch.
Fig. 5 is a schematic diagram of a transmission employing a one-way clutch structure in the prior art.
Detailed Description
The technical solution of the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.
According to the hydraulic control system and the corresponding downshift strategy, the hydraulic control system is composed of a high-pressure oil path, a gear switching oil path, a locking separation oil path and a lubricating oil path. The main functions of the hydraulic system are as follows:
1. the switching of P/R/N/D gears is realized by controlling the switch states of 5 hydraulic actuators (a first clutch, a second clutch, a third brake, a fourth brake and a fifth clutch), wherein the D gear is divided into six gears D1/D2/D3/D4/D5/D6.
2. And controlling the locking/unlocking state switching of the hydraulic torque converter according to different working conditions. The working condition that torque needs to be increased such as starting/climbing is in an unlocking state, and the working condition is in a locking state after a certain vehicle speed is reached, so that high transmission efficiency is ensured.
3. And the cooling/lubricating flow is controlled, and the lubrication of each friction pair and the heat exchange of the gearbox assembly are realized.
In order to improve the gear shifting quality and effectively reduce the downshifting impact of the 2-gear downshifting and the 1-gear downshifting, a gear shifting oil path is hydraulically designed, and the specific components are shown in a figure 1, and a working state diagram of a second-gear A-D slide valve. In the figure, 1, A valve; 2. a one-way throttle valve; 3. a fourth brake; 4. a valve B; 5. an electromagnetic valve; 6. a valve C; 7, a pressure relief valve; 8. a D valve; 9. a fourth brake reaction chamber.
In the second gear, the first clutch and the third brake are operated. The working state of the first clutch provides a high-pressure oil supply path for the gear shifting valve, and the electromagnetic valve and the slide valve keep the first clutch in a combined state. The system oil path of the third brake is supplied with high pressure oil, and the solenoid valve and the slide valve keep the third brake in a combined state. The reaction chamber of the fourth brake is filled with oil and the fourth brake is switched off.
In the first gear, the first clutch and the fourth brake work. The working state of the first clutch provides a high-pressure oil supply path for the gear shifting valve, and the electromagnetic valve and the slide valve keep the first clutch in a combined state. The fourth brake is filled with oil, and the reaction chamber of the fourth brake is disconnected. The solenoid valve + spool valve maintains the third brake in a pre-charge state.
As shown in fig. 1, when the gear is in the 2-gear position, the electromagnetic valve 5 does not work, the output pressure is 0, the control oil pressures of the leftmost valves of the a valve 1, the C valve 6 and the D valve 8 are all 0, the a valve 1, the C valve 6 and the D valve 8 are all positioned at the rightmost side of the empty valve core under the action of the spring, and in this state, the main oil pressure enters the fourth brake reaction cavity 9 from the core hole of the D valve 8; the feedback oil pressure of the brake enters the right end of the B valve 4 through the hole of the C valve 6, so that the B valve 4 moves leftwards, and the oil in the oil chamber of the fourth brake is discharged through the pressure release valve.
The relationship between the fourth brake 3 and the fourth brake reaction chamber 9 is shown in fig. 2, fig. 2 is a schematic diagram of the fourth brake, a closed and independent fourth brake oil chamber is arranged in the brake, and a fourth brake reaction chamber also exists in the fourth brake, when pressure oil enters the brake oil chamber from an inlet of the fourth brake oil chamber, the oil chamber can be expanded, and simultaneously the volume of the fourth brake reaction chamber can be compressed, so that the oil in the fourth brake reaction chamber is removed; when pressure oil enters from the inlet of the fourth brake reaction cavity, the fourth brake reaction cavity can be enlarged, and the volume of the fourth brake oil cavity can be correspondingly compressed, so that oil in the fourth brake oil cavity is discharged.
When the gearbox executes 2-1 gear, the hydraulic control system firstly finishes the pre-oil filling process for the fourth brake 3, the process is finished before the transmission is switched to 1 gear, the oil circuit of the fourth brake finishes base oil pressure (pre-oil filling), the pressure is not enough to enable the brake to be just at a critical point to be engaged, the specific execution operation is as follows, the current of the electromagnetic valve 5 is controlled to enable the electromagnetic valve 5 to output proper pressure oil, the pressure oil enables the B valve 4 to move rightwards, and the main oil pressure enters the brake cavity to finish pre-oil filling; because the fourth brake reaction cavity 9 is also filled with certain pressure oil in the relation of controlling oil pressure, the electromagnetic valve 5 finishes the quick oil filling time of the brake at the moment of switching the 1 gear. At the moment, because the reaction oil cavity has pre-stored oil pressure, the pressure can buffer the system working pressure in the brake oil cavity, and the D brake finishes the stable engaging process, so that the impact in the 2-1 gear is avoided. The operation of the valves in first gear is shown in fig. 3. FIG. 3 is a schematic view of the operating states of the first gear A-D spool valve of the embodiment of the present invention.
The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention cannot be limited thereby, and any modification made on the basis of the technical scheme according to the technical idea proposed by the present invention falls within the protection scope of the present invention; the technology not related to the invention can be realized by the prior art.